code: def _pipeline_names(est, in_names=None):
      names = in_names
      for name, trans in est.steps:
          if trans is not None:
              names = transform_feature_names(trans, names)
      return names
  
file_path: eli5/eli5/sklearn/transform.py
imports: import numpy
  from sklearn.pipeline import Pipeline, FeatureUnion
  from sklearn.feature_selection.base import SelectorMixin
  from sklearn.preprocessing import MinMaxScaler, StandardScaler, MaxAbsScaler, RobustScaler
  from eli5.transform import transform_feature_names
  from eli5.sklearn.utils import get_feature_names
label_desc: Use image node_id 3 for calling a global function with example usage: _pipeline_names(est, in_names) and returns: names